Reduced graphene oxide on silicon heterojunction for self-powered photodetection

A heterojunction diode was fabricated by depositing reduced graphene oxide (rGO) on n-type silicon. The device was exposed to UV irradiation for periods of up to 10 min and temperatures between 50 K and 350 K. The current-voltage measurements show an increment in conductivity with UV irradiation of 365 nm in the whole temperature range. The photoresponse with no external bias (self-powered) shows maximum responsivity and detectivity of 0.2 A/W and 7.5x10⁹ Jones, respectively, at 223 K. The response and recovery times for on-off switching of UV light range from 20 to 50 ms. The rGO, obtained from hydrothermal carbonization of sucrose, can be produced at low-cost cost and with high yields, and is compatible with silicon device technology. The results indicate that the rGO-based device can be useful for self-powered photodetection. We will present our analysis on temperature-dependent photoconduction mechanisms.